The present invention generally relates to the field of vehicle security and particularly, to the field of computer processing-based vehicle-installed systems that perform a plurality of safety and security functions.
The marketplace teems with products designed to enhance the safety and security of vehicles. The products range from simple mechanical devices to sophisticated computer-controlled systems. Because of the enormity of the automobile market, most if not all of the technology in vehicle safety and security can be found in devices and systems directed to the automotive industry. Products in the field of automotive safety and security are often differentiated according to the entity intended to perform the product installation. The most complex systems typically are designed to be installed in or are integrated during the construction of a vehicle by the manufacturers of the vehicle. Other systems, often referred to as after-market products, typically require less integration with basic vehicle systems and are typically designed to be installed either by trained personnel operating out of a vehicle dealership or security system installation center, or by the end user of the vehicle. The simplest systems normally are specifically designed to be used and/or installed by the end-user of the vehicle, where the assumption is that no installation training is required.
With respect to vehicle manufacturers, nearly all motorized vehicles are presently manufactured with some level of built-in security system. These systems, commonly referred to as Original Equipment Manufacturer or OEM systems, range from mechanical ignition locks that prevent ignition and steering wheel turning until a vehicle is activated by a key, to computerized systems that not only disable the vehicle when an attempted theft or vandalism is detected, but also provide features like automatic door locks, automatic trunk latch, dome light control, headlight control and remote control of various accessories. These electronic security systems are wired during the manufacturing process and are fully integrated into the rest of the vehicle""s electrical system.
The after-market vehicle safety and security products, which are either trained personnel or end user-installed, range from mechanical bars that are literally locked to the steering wheel to prevent wheel rotation, to multi-function electronic systems. The after-market mechanical devices are often but a slight deterrent because they can be easily bypassed. For example, the typical lock bar can be circumvented by severing the steering wheel and hard wiring the ignition switch. In contrast, the after-market electronic systems are more difficult to disarm. These systems, however, are correspondingly more expensive and more difficult to install. In the marketplace, these systems are often offered to the consumer as an option by the vehicle dealership.
As noted above, the after-market electronic systems are typically less complex than the manufacturer-installed systems, but are still quite labor-intensive to install and de-install. After-market electronic systems, though seemingly less vehicle-integrated than the manufacturer systems, typically require a partial disassembly of the motorized vehicle, and interfacing with the vehicle""s electrical system. This interfacing requires wiring dedicate specifically to the security system, and integrating the new wiring with the vehicle""s existing wiring. The existing and new wires normally must be cut, spliced, and/or crimped as part of the process of installing the after-market systems. Such extensive manipulation of electrical wiring potentially introduces defects into the installed electronic security systems, and in the worst case, into the vehicle""s other electrical systems. For example, a poorly crimped wire is susceptible to failure as a result of shock, vibration, exposure to moisture and other corrosive materials. Potentially, within months after a defective crimp is made, an electronic security system or an aspect of the vehicle""s electrical system could suddenly fail.
For dealer-installed systems, therefore, dealerships attempt to avoid such problems by employing expert installers. However, because of the substantial expertise needed by the installers, the dealerships incur a substantial labor cost. Substantial costs are also potentially incurred where a de-installation of an electronic security system is necessary. Sometimes, for example, the after-market product has been previously installed by the manufacturer. Because such systems are typically an optional feature at the time of vehicle purchase, often a vehicle buyer does not want the already-installed security system. In that event, the dealership must bear the substantial expense of de-installation or risk losing the sale.
With respect to the after-market electrical systems directed to the end-user, most consumers are technically incapable of installing an electronic security system, and are particularly unwilling to cut and splice the wires in a vehicle""s electrical system as is required to install the security system. Still other consumers do not have the tools or time to install a vehicle security system and, therefore, the installation of an electronic security system must be performed, at a substantial additional expense, by a trained technician. Nevertheless, vehicle dealerships are highly motivated to dealer-install vehicle security systems as options on their vehicles because of the normally high profit margin associated with such vehicle options. Unfortunately, because of the high labor cost, many vehicle owners are often deterred from having sophisticated security systems installed in their existing vehicles.
Thus, a need exists for a vehicle safety and security system that has the sophistication and multi-function capability desired by many vehicle owners while not exacting the prohibitive costs associated with installing and de-installing such systems. The needed vehicle safety and security system includes an effective theft-deterring capability comparable to other sophisticated security systems and preferably seamlessly incorporates other desirable safety and security features. Such features include a battery saving function to preserve a vehicle""s battery charge capacity in the event of potential loss of battery power, such as when the headlights of a vehicle remain lit after the vehicle""s engine has been deactivated. Another preferable feature is a battery warning function that informs the vehicle user of the charge capacity of the battery. Further, a need exists for a system that preferably includes an accident safety capability. The system disconnects the battery after a collision involving the vehicle as a measure for minimizing the probability of a vehicle fire caused by an electrical short circuit. Also, a system is needed that preferably includes intelligent control of and communication with the electronic accessories, including pre-existing and later-installed accessories, of a vehicle that are powered using the vehicle""s electrical system.
The need for a sophisticated system that performs the above safety and security functions with easy installation and de-installation has, until now, not been effectively met. With respect to theft-deterrence, one of the more common measures has been to disconnect the vehicle""s battery. The first battery disconnect system used as a safety and anti-theft device was disclosed by F. M. Blake in U.S. Pat. No. 1,654,450 on a method and apparatus of disconnecting the battery of a motorized vehicle by means of a hidden plunger/switch. Blake had three positions on the disclosed plunger/switch. The first position allowed normal operation of the vehicle. The second position inserted a resistive means in the electrical circuit of the battery and the starter so that the parking lights could operate but the starter and the horn would be disabled. The third position disconnected the battery completely from the electrical circuit of the vehicle. Since then, numerous variations of the same concept have been marketed and/or patented. As the technology and the resources have advanced, so have the system designs for disabling a motor vehicle by disconnecting the battery. However, a sophisticated theft-deterrence system based on battery disconnection that is easily installed in a vehicle and that seamlessly incorporates other safety functions has not been disclosed by the prior art.
An aspect of sophisticated vehicle safety and security systems is the sensing and characterizing of external stimuli, such as the motion, shock or vibration subjected upon the vehicle. The reliability of a security system depends on an accurate characterization of these external stimuli. Otherwise, a security system may falsely trigger an alarm, or worse yet, not trigger one at all while the protected vehicle is being violated. The burden of an accurate characterization and analysis lies not only on the sensors deployed about the vehicle by the security system, but also on the methods of processing the information obtained from the sensors. In recent years, there has been a substantial development in the sensitivity and discrimination of sensors and the methods for processing their responses to improve overall system performance. Acoustic energy, sonic and ultrasonic waves, infrared, radar, heat sensing and pressure sensing have been applied to develop better and more reliable sensors for vehicular use.
Regardless of the medium used to detect a stimulus, there are three levels of sophistication in the technology of detection. The first and simplest level is the measurement of amplitude or intensity of stimuli and the comparison of that amplitude or intensity with a pre-selected threshold. The second level of sophistication has multiple thresholds of intensity for a measured signal to determine multiple levels of hazard to which a vehicle may be exposed. The third and most complex level is exemplified by first having a measured signal operated on by plurality of filters to distinguish different frequency bands. Then the amplitudes in the bands are compared with pre-stored parameters to identify the level of hazard to which the vehicle is being exposed. The pre-stored amplitude and frequency contents may be re-programmed in the field by either the consumer or the installer. The U.S. Pat. No. 4,845,464 by Drori et al. teaches such a system, where such amplitude and frequency contents are measured and stored for comparison with pre-stored parameters.
On the same level, U.S. Pat. No. 5,598,141 discloses several embodiments where an identity or similarity test is conducted to between a measured signal and a stored signal. This patent discloses an embodiment where a Von Neumann architecture is used for similarity or identity testing by a Dynamic Time Warping (DTW) algorithm. In the DTW algorithm, the characteristics of the measured signal and the sample signal with time are treated as respective vector sets and a warping function is determined for each of the sets. The warping function can also be determined from the amplitude values rather than from the time characteristics. A distortion matrix is formed of these elements which may represent the similarity of the vector sets. In the DTW algorithm, the characteristics of the amplitude with time are generally subjected to a normalization process such that similar amplitude sequences are treated as similar events.
In yet another embodiment, a computer processes sensor signals using xe2x80x9cFuzzy Logic.xe2x80x9d Fuzzy logic is based upon the theory that sharply demarcated values and logic are not necessary elements of a signal recognition process. Rather, the theory suggests that variables can have fuzzy values and blurred limits. With fuzzy logic, a degree of hazard is calculated that is not limited to a definite value. In applying fuzzy logic to a vehicle security system, an alarm device may be activated whether a xe2x80x9chazardxe2x80x9d value exceeds or is just below a predetermined threshold value.
Systems such as those discussed above that use sophisticated signal processing technology in vehicle safety and security systems can improve the overall reliability of the detection and characterization of external stimuli. However, to accomplish this, a plurality of transmitters and receivers of the chosen energy medium are required. Moreover, to implement such systems, sophisticated computing hardware is necessary. Such computing hardware, however, is costly and has substantial power requirements. With respect to the sensors that provide the input to such systems, their calibration for sensitivity and temperature and the physical coupling of the sensors to a vehicular body are issues that potentially translate into high material and installation costs. Such consequences of applying sophisticated technology in motor vehicle security systems often make their use impractical. Thus, a need exists for an inexpensive method of measuring external stimuli, having a simple hardware/software interface, consuming low power and having high reliability in characterizing external stimuli.
As outlined above, a need exists for a multi-function, easily installed, vehicle safety and to security system that includes battery saving and battery condition warning capabilities. Systems that perform these functions have been in existence for some time as battery failure has always been a problem in motorized vehicles.
One of the most common causes of battery failure is accidental battery discharge. Accidental battery discharge can occur because of vehicle operator error, such as when in an inactive vehicle, an electrical load such as headlights or parking lights remain active for an extended period. Accidental battery discharge is also caused by auxiliary equipment loads powered from, for example, the cigarette lighter plug. Many vehicle manufacturers have addressed the problem of accidental battery discharge and have implemented electrical wiring changes in their vehicles to attempt to prevent it. However, wiring changes alone cannot prevent all accidental battery discharges. For example, while the cigarette lighter socket and the headlights can be wired into the ignition without affecting their versatility, the parking lights, on the other hand, cannot be wired into the ignition circuit. A vehicle operator must be free to leave the vehicle unattended with the parking lights activated. Further, a vehicle""s interior lights must be designed to be activated when the engine is inactive and the doors of the vehicle are opened.
To address these issues, battery saver systems that prevent or at least minimize battery drain have been developed as after-market products. As certain conditions are met, a battery saver system saves the charge on the battery by disconnecting the battery from the rest of the vehicle""s electrical system. In U.S. Pat. No. 5,089,762 to J. M. Sloan, a battery disconnect device is disclosed in which a microprocessor iteratively compares a battery voltage signal with a cutoff voltage, the level for which depends partially on the ambient temperature surrounding the battery. If the battery voltage is less than or equal to the cutoff voltage level, then after a short period of time, the battery is disconnected by a battery disconnect signal from the microcontroller. Similarly in U.S. Pat. No. 5,691,619 issued to S. Vingsbo, a battery safety switch is provided which continuously monitors the battery voltage and compares it to a reference voltage. A relay is disengaged subsequently to detecting a battery voltage that is of lower magnitude than the reference. These systems, as well as others in the prior art, do not perform their battery saving function in combination with other vehicle safety and security functions. In fact, as single function systems, these devices at times may interfere with the performance of other vehicle safety or security devices.
Another common cause of battery failure is a faulty battery. A battery may be faulty because of aging, low electrolyte (poor maintenance), a weak or non-functioning alternator, a malfunctioning regulator, corrosion on the battery electrodes or a manufacturing defect. This kind of failure typically becomes observable over a longer period of time than if a battery loses charge capacity simply because of a power-draining active load. To address this issue, battery condition warning systems have been developed that continually or periodically analyze a battery""s charge capacity. These systems often provide a warning to the vehicle operator when the charge capacity in the battery is low. For example, in U.S. Pat. No. 4,816,768, K. Champlin discloses a medium-scale integration (MSI) and CMOS implementation of a battery testing circuit. The testing device performs small signal measurements of a battery""s dynamic conductance and provides for displaying either quantitative or qualitative assessments of the battery""s condition. In U.S. Pat. No. 5,438,270, J. Harper et al. discloses a battery tester that includes a circuit that provides a battery charge and current level signal. The signals are based on a comparison between a first ratio of the battery potential when the battery is unloaded and a second ratio of the loaded battery potential. In U.S. Pat. No. 5,629,680, issued to S. K. Makhija, a self-contained vehicle current drain tester with memory saver is disclosed. The tester includes a measurement current loop, an offset circuit and a fail indicator. A current sensor generates a measurement signal in response to current flowing in the current loop. Like the battery saver systems in the prior art however, the above devices are not directed towards seamless integration into a multi-function vehicle safety and security system. Thus, a need exists for a battery condition testing and warning system that warns the vehicle operator about forthcoming battery problems and seamlessly integrates into an easily-installed multi-function vehicle safety and security system.
A need also exists for a multi-function, easily installed, vehicle safety and security system that includes a battery-disconnect capability in case of a collision involving the vehicle. It is well known in the technology of vehicular safety that as a result of an automobile accident in which the body of the vehicle is damaged, a serious risk of a fire exists. Of the fires that are started in the engine compartment because of an accident, about 80% are caused by an electrical short circuit. Because of this threat, vehicle manufacturers such as Mercedes Benz, BMW and General Motors have designed and implemented systems in many of their luxury models to minimize the probability of vehicle fires caused by electrical short circuits. A need exists however, for an after market multi-function vehicle safety and security system that seamlessly incorporates such an accident safety capability as one of its functions.
A need further exists for an easily installed multi-function vehicle safety and security system that effectively communicates with accessories, such as the vehicle door locks, dome light and trunk latch. There are several known methods of communication between a main security system unit, which is often installed under the hood, and its accessories, which are often installed in the passenger compartment, inside the door panels or in the trunk. The most commonly practiced method is to install dedicated wiring to selectively control the accessories. In some implementations, more than one wire is run to each accessory to selectively control corresponding functions performed by the accessories. Hard wiring, however, is tedious work and normally requires a working knowledge of a vehicle""s electrical system.
To avoid the problems associated with hard wiring, wireless systems have been devised that potentially only require wiring for the systems"" power supplies. Wireless methods using radio frequency transmission have, however, inherent drawbacks. In a radio-controlled security system for a vehicle, interference signals coming from similar anti-theft systems in nearby vehicles, garage door openers, electrical storms, stray harmonics of broadcast radio or the like, could inadvertently operate the vehicle""s accessories or the security system itself. Ultrasonic and infrared signals may be used for communication, but for these methods it is almost impossible to transmit the signal from the engine compartment to the passenger compartment or to the trunk of the vehicle.
To communicate with vehicle accessories, another practice is to use a vehicle""s existing power wiring. U.S. Pat. No. 4,463,340 by Adkins et al. discloses a method of imposing coded signals on a vehicle""s power transmission circuit. A coded signal is imposed on the vehicle""s power transmission circuit using a high power switch that loads the circuit at high speed. This method imposes a signal on the power transmission circuit that is rich in harmonics, and which, because of interference, could render useless sensitive electronic equipment, like a radio or internal computer. The patent, however, neither addresses nor provides any solution for the problem of interference. U.S. Pat. No. 5,539,388 by O. S. Modgil discloses a method that resolves the interference problems by imposing a signal on the power transmission circuit that resembles the noise induced on the power transmission circuit by other electrical systems of the vehicle, like the spark plugs and alternator. The imposed signal however differs from such noise in periodicity. Further, electronic equipment that is provided in most vehicles suppresses such noise. Because the imposed signal is only a few millivolts, this method requires sophisticated and relatively expensive means to isolate the imposed coded signal from the imposed noise. In U.S. Pat. No. 5,677,663 by Sansome, a method is disclosed in which a terminal receives power produced by a power supply, and a signal modifier modifies a characteristic of the power produced by the power supply. A reader detects the presence of the verification signal and an enabler enables the vehicle to be driven when the presence of the verification signal is detected.
All of the vehicle communication systems discussed above and in the prior art that use the power transmission circuit of the vehicle impose a new signal on the DC power transmission signal. However, the battery in most motorized vehicles, being a low resistance and high capacitance device, resists having a signal imposed on it. Furthermore, although an imposed signal may be identifiable a significant distance away from the battery, near the battery, the magnitude of the imposed signal is lower, making identification much more difficult. Thus, the integrity of the imposed signal in the prior art systems varies from location to location within the power transmission circuit of the vehicle. Temperature, stray capacitance and capacitance to chassis ground also have significant effects on the quality of imposed signal.
Compounding the problems associated with such methods, modern vehicles having sub-systems like air bags, anti-skid systems, anti-lock breaking systems, and the like, require a clean, uncontaminated supply of power. Consequently, vehicle manufacturers are beginning to install localized noise filters and noise suppression systems under the dashboard or elsewhere about the vehicle. The installation of such systems makes ascertaining the true magnitude of an imposed signal that is received at a particular point in a power transmission circuit even more difficult. Thus, a need exists for system that includes a capability of communicating with vehicle accessories but that is not hampered by such communication problems.
The present invention provides an electronically-based, self-contained safety and security system for a vehicle having an existing power transmission circuit including a battery that can be readily installed and made operational by an individual having no special training using common household tools. The safety and security system requires the installation of no dedicated wiring in the vehicle. Furthermore, the system preferably installs without any cutting or splicing of the wiring in the vehicle""s electrical system.
A preferred embodiment of the present invention includes an electrical activity sensor coupled to and sensing electrical activity on the direct current power transmission circuit, a motion sensor sensing vibration associated with the vehicle, a battery-disconnect switch electrically interposed in the direct current power transmission circuit; and a controller having inputs to receive signals from the electrical activity and motion sensors and an output to communicate with and control the switch. The electrical activity sensor has an electrical activity sensor output producing an electrical activity output signal functionally related to a voltage detected on the direct current power transmission circuit. Similarly, the motion sensor includes a motion sensor output that is electrically coupled to the input of the controller and produces a motion sensor output signal functionally related to any vibration detected within the vehicle.
As such, it is an object of the present invention to provide a novel battery saver for a vehicle that automatically detects a condition leading to an accidental discharge of the battery, and prevents it. The system and method of the present invention achieves this object in that the controller first analyzes the electrical activity output signal of the electrical activity sensor to determine a load on the direct current power transmission circuit. The controller then transmits a battery-disabling signal to the switch thereby opening the switch when the electrical activity output signal varies by a preset amount from a predetermined ambient condition level. Peferably, the present invention further includes an intelligent module electrically interposed in and sensing electrical activity on the direct current power transmission circuit. The intelligent module has an output electrically coupled to one or more electronic accessories in the vehicle and deactivates the electronic accessory from an active state when the intelligent module senses that the battery is overloaded. The intelligent module senses an overload when it detects the electrical activity on the direct current power transmission circuit falling a preset amount below a predetermined ambient condition level.
It is also an object of the present invention to provide a novel system and method for deterring theft. The system and method of the present invention achieves this object in that the controller first analyzes the electrical activity output signal of the electrical activity sensor to identify when the electrical activity output signal contains an electrical signature of an ignition switch in motion. The controller then calculates a theft-deterrence value based on the analyzed electrical activity and transmits a battery-disabling signal to the battery-disconnect switch when the theft-deterrence value surpasses a predetermined battery-disconnect threshold level.
It is another object of the present invention to provide a novel battery analyzing system and method for a vehicle that automatically detects the charge-capacity of the battery and warns the user of the system audibly and/or visually. The system and method of the present invention achieves this object in that the controller first analyzes the electrical activity output signal of the electrical activity sensor when the vehicle""s starter is activated to determine the battery condition. The controller then transmits on the direct current power transmission circuit a battery condition signal containing data on the battery condition to a battery condition reporting module. The battery condition reporting module is electrically interposed in the direct current power transmission circuit and reports to the user the battery condition information that is encoded in the battery condition signal.
It is another object of the present invention to provide a novel accident safety system and method for a vehicle. The system automatically disconnects the battery for the power transmission circuit when the vehicle is involved in a forceful collision. The system and method of the present invention achieves this object in that the controller first analyzes the motion sensor output signal of the motion sensor to identify whether the motion sensor output signal contains a vibration signature of a collision. The controller then transmits a battery-disabling signal to the switch when the motion sensor output signal matches the vibration signature to a preset degree.
It is another object of the present invention to provide a system and method for transmitting telemetry and control signals including data to electronic accessories interposed on the power transmission circuit, without including any dedicated wiring for the communication. The system and method of the present invention achieves this object in that the controller encodes the data in the signals by transmitting to the switch a sequence of battery-enabling and disabling signals. The time between enabling and disabling signals comprises the data signal. A receiver electrically coupled to the direct current power circuit receives the data signal and decodes it into data. Preferably, the present invention includes a constant current source interposed in the direct current power transmission circuit and electrically in parallel with the switch. The constant current source, when enabled, preferably supplies an ambient condition voltage to the direct current power transmission circuit. When the controller disables the battery by transmitting a disabling signal to the switch, the voltage on the direct current power transmission circuit shifts to the ambient condition voltage.
It is another object of the present invention to provide a seamless integration between these aforementioned systems and methods such that they are performed by a single unified system.
These and other objects, features, enhancements and advantages of the present invention will become apparent upon consideration of the following detailed description of the invention and the accompanying drawings.